Test plan is a strategic document in order to do testing.
it consists of test plan id, reference documents,Revision
history,Test schedules,Test Item,Test
process,Resources,Risks and mitigations,Training..those type
of info..

Test plan: it is a statagic document. It consists of
objectives ,scope ,approach and focus in software testing
effort.
it is prepared by Test Lead
in this phase he will prepare Test plan Document.Here he
has follows the below approachs
1. what to test
2. who to test
3. how to test
4. when to test.

Test plan:It describes how testing will be accomplished.It
is very essential for effective testing and it will take
about one third effort of the total test effort.It is a
contract between the testers and the project team and user
describing the role of testing in the project.
It consists of
1)Test scope 2)Test Objectives 3)Assumptions 4)Risk Analysis
5)Test Design 6)Roles and responsibilities 7)Test schedule
and resources 8)Test Environment 9)Communication approach
10)Test Tools

4. Test plan:It describes how testing will be
accomplished.It
is very essential for effective testing and it will take
about one third effort of the total test effort.It is a
contract between the testers and the project team and user
describing the role of testing in the project

test plan is a doc. That gives entaire idea about the
testing. it mainly consists of Objective, scope,
approches,and focus of the s/w testing efforts, .it mainly
consists of Objective : it specifies goal.
scope : How to fullfil the objective and that are the
process we need to impliment.
Approch: what are the testing approches and testing
techniquecs we need to take
pass/fail: createrial
entry/ exit creatirial.
schedules.
risk anlysys:
which features to be te not to be test:
which deliverable we need to submit at the end of testing:
which to we need to use :

Test plan is a document which drives all future testing activities...This is where we decide,how many engineers are needed,Who should do what,how to track defects etc.
The contents of test plan are:Objective,Scope,Approach,Assumption,Risks,Mitigation Plan,Test automation,Schedule,Defect tracking,Testing methodologies,Entry & Exit criteria,Deliverables,Test Environment,Roles & Responsibilities and Templates